In a large saucepan, melt the butter over low heat. Add the marshmallows and stir until completely melted.
Remove from the heat and add the Rice Krispies, stir until well coated.
Using a buttered spatula, press evenly into a greased 9x13 pan. Let cool.
Cut into rectangles.
Melt the green candy melts in a double boiler or in the microwave at 50% power for 30 second intervals, stirring in between until completely melted. Repeat with the chocolate or black.
Dip the crispy treat into the melted chocolate to make the head.
Press into chocolate sprinkles to make the hair.
Add the melted chocolate candy into a ziplock bag, zip close and cut off a small piece of the corner. Pip eyes and a mouth.